How to deal with ridiculous amounts of distrust and jealousy in a relationship? Need Advice

So I've been in a relationship with my boyfriend for around 10 months now. When it's good it's great, I love being around him, he makes me feel so beautiful, thinks I'm funny, makes me feel safe, I love being with him. The issue is me. I have really bad trust issues and get so jealous and it causes me a ton of anxiety and I have breakdowns and it's really straining both of us.

For reference, we're both 23. I'm currently in counseling at my college but seeking long term therapy, and I plan to go to the doctor soon because my counselor suggested I may be bipolar, along with general depression and anxiety, so I'll be looking into meds possibly. I also recently lost my mother, so I've been grieving and trying to deal with the loss and things have just been tough and stressful.

It's just been getting worse. Recently I've vented to him and tried to explain my feelings about how I feel he doesn't like me or will find someone better because I had a really bad breakdown and he wasn't very responsive other than like "that sucks, I wish I could help, I don't know what to say". I sent him sexy pictures that he's usually all about and gushes about how I look, but he just sent hearts and that was it. If he hangs out with coworkers or friends for longer than usual it makes me anxious and upset (doesn't help he has mentioned a coworker seemingly having a crush on him and he works with a ton of women). He has a lot of female friends, snapchat is like his #1 social media app and is constantly on it talking with people, had a snap score around 70,000. He has a long list of exes and hook ups (some he's still in contact with), and I have none. Girls message me about him, one girl messaged him trying to say I was being shady behind his back (I wasn't and he knew that) but she was just clearly trying to sabotage me and our relationship to get with him (she's flirted with him before).

Theres other things but it's mostly all very innocuous mundane things that I know logically aren't a symptom of a bigger issue but my mind can't help but think he's lying or being sketchy or just doesn't like me as much anymore. I know a lot can boil down to I'm an introvert and he's he's extrovert so yeah he talks and hangs out with other people a lot. I just... it's very tough to fight the feelings and thoughts.

I know I can ruin my relationship by being so paranoid, and I'm scared I already have. I want to do what I can to salvage it and what he thinks of me but these thoughts and feelings are so powerful. I try to talk to him about it but no matter how much he reassures me I find something else to get stuck on. What can I do to try to break these bad toxic habits? Any positive criticism and help is appreciated.